feat(ui): refine the sheet's beats, the lip's return and the hop's sink and swell

app/src/main/java/com/droiddeck/launcher/ui/FrontEndContent.kt

@@ -138,12 +138,12 @@ internal fun Pane(
             pages[s.pageKey] = page
             if (s.pageKey !in origins) PageOrigin.take()?.let { o ->
                 // A hop's page came out of its own rail item, and is that item's content.
-                origins[s.pageKey] = o.translate(-paneAt[0]).let { if (it.owner == null) it.ownedBy(railContent) else it }
+                origins[s.pageKey] = inPane(o.translate(-paneAt[0])).let { if (it.owner == null) it.ownedBy(railContent) else it }
             }
         } else if (target != before[0] && target !in origins) {
             // A section's own page opened from a control in it (an emulator's card, a ROM's) floods
             // out of that control and belongs to what was showing; a hop's comes out of its rail item.
-            PageOrigin.take()?.let { o -> origins[target] = o.translate(-paneAt[0]).let { if (it.owner == null) it.ownedBy(before[0]) else it } }
+            PageOrigin.take()?.let { o -> origins[target] = inPane(o.translate(-paneAt[0])).let { if (it.owner == null) it.ownedBy(before[0]) else it } }
         }
         before[0] = target
         val targetNow by rememberUpdatedState(target)
@@ -175,8 +175,16 @@ internal fun Pane(
             },
             label = "pane",
         ) { key ->
-            val shown = (if (page != null && key == s.pageKey) page else pages[key])
+            val drawn = (if (page != null && key == s.pageKey) page else pages[key])
                 ?: { Content(s, if (key == "games") gameShown[0] else key, a, Modifier.fillMaxSize(), onSelect, onAndroidAppClick, onOpenDeveloperOptions, onRequestWirelessAdb) }
+            // A hop leaving this content: it sinks back as the dot leaves it (and comes forward
+            // again, freshly drawn, when the hop is undone).
+            val hopSink by androidx.compose.animation.core.animateFloatAsState(
+                if (Hops.sinking == key) 1f else 0f, Motion.tw(260), label = "hopSink",
+            )
+            val shown: @Composable () -> Unit = {
+                Box(Modifier.fillMaxSize().graphicsLayer { val k = 1f - 0.05f * hopSink; scaleX = k; scaleY = k; alpha = 1f - 0.35f * hopSink }) { drawn() }
+            }
             run {
                 DisposableEffect(key) { onDispose { if (key != livePage && key != targetNow) { pages.remove(key); origins.remove(key) } } }
                 val from = origins[key]
@@ -204,6 +212,14 @@ internal fun Pane(
     }
 }
 
+/**
+ * An origin left of the pane (a rail item a hop flew to) starts half inside it, at the item's
+ * height: the page swells out of the pane's edge beside the item. Wholly outside, its tile was a
+ * bar that raced across from the far edge.
+ */
+internal fun inPane(o: Origin): Origin =
+    if (o.bounds.right > 0f) o else o.translate(Offset(-o.bounds.right + o.bounds.width / 2f, 0f))
+
 @Composable
 private fun Backdrop(art: File?) {
     val colors = MaterialTheme.colorScheme

app/src/main/java/com/droiddeck/launcher/ui/FrontEndScreen.kt

@@ -483,6 +483,7 @@ private fun FrontEndScreenBody(s: FrontEndState, a: FrontEndActions, page: (@Com
             // Another section: no way back to keep, and no sheet to put back.
             Hops.origin = null
             Hops.restore = null
+            Hops.sinking = null
             // Picked from the rail, Desktop starts at its hero; back from one of its pages it is where it was.
             if (key == "desktop" && selected != "desktop") DesktopMemory.scroll = 0
             selected = key

app/src/main/java/com/droiddeck/launcher/ui/Hop.kt

@@ -60,6 +60,9 @@ internal object Hops {
     /** The hop the page on screen was reached by, while B can still undo it. */
     var origin by mutableStateOf<HopOrigin?>(null)
 
+    /** The pane content a hop is leaving (a rail key): it sinks back as the dot leaves it. */
+    var sinking by mutableStateOf<String?>(null)
+
     /** Set while a hop's dot is flying: the rail item its selection has already glided to. */
     var railPreview by mutableStateOf<String?>(null)
 
@@ -100,6 +103,8 @@ internal object Hops {
             arrived++
         }
         if (railAt == null || Motion.scale == 0f) { finish(); return }
+        // The surface the control is on sinks as its dot leaves, and stays down as it goes.
+        sinking = origin.rail
         Flights.fly(Flight(
             origin.bounds, to = { railAt.center },
             onHalf = { railPreview = origin.dest },
@@ -114,6 +119,7 @@ internal object Hops {
     fun back(close: () -> Unit): Boolean {
         val o = origin ?: return false
         origin = null
+        sinking = null
         val railAt = railBounds[o.dest]
         railPreview = if (railAt != null && Motion.scale != 0f) o.dest else null
         restore = o
@@ -130,7 +136,7 @@ internal object Hops {
     /** The page the hop opened has gone some other way: there is no way back to keep. */
     fun forget(pageKey: String?) {
         val o = origin ?: return
-        if (pageKey != o.page) origin = null
+        if (pageKey != o.page) { origin = null; sinking = null }
     }
 
     /** Screen density, for the rail item's corner; set by the front end. */

app/src/main/java/com/droiddeck/launcher/ui/LiftSheet.kt

@@ -221,6 +221,8 @@ internal fun LiftHero(
     var travel by remember { mutableStateOf(1) }
     // The control to focus once a sheet put back by a hop's B has lifted, instead of the first chip.
     var focusOnLift by remember { mutableStateOf<String?>(null) }
+    // Set as the sheet closes and Play lands: the lip may come back before the sheet has quite gone.
+    var lipBack by remember { mutableStateOf(false) }
     val pull = remember { Animatable(0f) }
     val sink = remember { Animatable(0f) }
     val lift = remember { Animatable(0f) }
@@ -268,6 +270,7 @@ internal fun LiftHero(
     }
     LaunchedEffect(open, launching) {
         if (open && !launching) {
+            lipBack = false
             shown = true
             onOpen()
             fold.snapTo(0f); foldTop.snapTo(0f)
@@ -284,7 +287,8 @@ internal fun LiftHero(
                     launch { ride.animateTo(1f, Motion.sp(0.7f, 380f)) }
                     launch { hot.snapTo(1f); delay(Motion.ms(100).toLong()); hot.animateTo(0f, Motion.tw(200)) }
                 }
-                pieces.forEachIndexed { i, p -> launch { delay(Motion.ms(260 + i * 55).toLong()); p.animateTo(1f, Motion.tw(220)) } }
+                // Each piece on its beat from the Lift, as the reel has it: 260ms + 55ms a piece after it starts.
+                pieces.forEachIndexed { i, p -> launch { delay(Motion.ms(120 + 260 + i * 55).toLong()); p.animateTo(1f, Motion.tw(220)) } }
                 if (inputMode.inputMode == InputMode.Keyboard) launch {
                     val control = focusOnLift
                     focusOnLift = null
@@ -313,8 +317,11 @@ internal fun LiftHero(
                 launch { delay(Motion.ms(60).toLong()); lift.animateTo(0f, Motion.sp(1f, 380f)) }
                 launch { delay(Motion.ms(100).toLong()); ride.animateTo(0f, Motion.sp(0.55f, 300f)) }
                 launch { sink.animateTo(0f, Motion.tw(300)) }
+                // The lip tucks back under Play as it lands, not once every spring has settled.
+                launch { delay(Motion.ms(420).toLong()); lipGone.snapTo(0f); lipBack = true }
             }
             shown = false
+            lipBack = false
             lipGone.snapTo(0f)
             hot.snapTo(1f)
         } else {
@@ -332,11 +339,12 @@ internal fun LiftHero(
     val touchOnly = inputMode.inputMode == InputMode.Touch
     val lipFocus = remember { FocusRequester() }
     var lipFocused by remember { mutableStateOf(false) }
-    val lipWanted = !open && !shown && (playFocused || playHovered || touchOnly || lipFocused)
+    val lipWanted = !open && (!shown || lipBack) && (playFocused || playHovered || touchOnly || lipFocused)
     val lipNow = rememberUpdatedState(lip)
     LaunchedEffect(lipWanted) {
         if (lipWanted) {
-            delay(Motion.ms(160).toLong())
+            // Back from the sheet it comes straight away; otherwise a beat after Play has focus.
+            if (!lipBack) delay(Motion.ms(160).toLong())
             val now = lipNow.value()
             lit = lipChanged(LipMemory.seen[key], now)
             LipMemory.seen[key] = now.toMap()

app/src/test/java/com/droiddeck/launcher/ui/InPaneTest.kt

@@ -0,0 +1,20 @@
+package com.droiddeck.launcher.ui
+
+import androidx.compose.ui.geometry.Rect
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertSame
+import org.junit.Test
+
+class InPaneTest {
+    @Test fun aRailItemLeftOfThePaneStartsHalfInside() {
+        val o = inPane(Origin(Rect(-200f, 300f, -20f, 420f), 14f))
+        assertEquals(-90f, o.bounds.left, 0.01f)
+        assertEquals(90f, o.bounds.right, 0.01f)
+        assertEquals(300f, o.bounds.top, 0.01f)
+    }
+
+    @Test fun aControlInThePaneStaysPut() {
+        val origin = Origin(Rect(40f, 300f, 200f, 360f), 12f)
+        assertSame(origin, inPane(origin))
+    }
+}